Conductor and electric machinery provided with it



R. RUDENBERG.

CONDUCTOR AND ELECTRIC MACHINERY PROVIDED WITH IT.

, APPLICATION FILED-OCT 18, I916. RENEWED.NOV.16,1920,- 1,370,156.

Patented Mar. 1, 1921.

UNITED STATES PATENT OFFICE.

REINHOLD RUDENBERG, or 'CHARLOTTENBURG, NEAR BERLIN, GERMANY, ASSIGNOR TO SIEMENS"SCHUCKERTWERKE G. M. B. 11., 0F SIEMENSTADT, NEAR BERLIN, GERMANY, A CORPORATION OF GERMANY.

CONDUCTOR AND ELECTRIC MACHINERY PROVIDED WITH IT.

Specification of Letters Patent Patented Mar. 1 1921.

Original application filed September 18, 1913, Serial No. 790,533; Patent No. 1,285,398, dated November 19, 1918. Divided and this application filed October 18, 1916, Serial No. 126,320. Renewed November16, 1920. Serial No. 484,510.

I! I l v 1 0 all whom 2t may concern:

Be it known that I, REINHOLD BUDEN- Bane, a German citizen, and resident of Charlottenburg, near Berlin, Germany, have invented certain new and useful Improvements in Conductors and Electric Machinery Provided with Them, of which the following is a specification My invention relates to electric machinery and more particularly to electric conductors to be used in connectionwith the same. The

particular objectofmy'invention is to pro vide-conductors adapted to greatly improve the electric effect of the machine carrying them.

bAsis well known tothose skilled in the art, conductors disposed in slots of the rotors of electric machines require being difficulties arisein connection-withthe sta- V tors of certain classes of electric machines,

such as highvoltage dynamos, where the conductors embedded in'the slots of the statorare surrounded by comparatively thickwalled tubes of insulating material which form a particularly strong hindrance to the escape of the heat to the outside.

Attempts have been made to dispose of this heat by making the conductors con nected with rotating parts of electric machinery as well as with transformers, electric heaters and the like, hollowor in other words to provide such conductors with a centrally located channel extending longitudinallythrough them, air or another cooling medium such as water being caused to pass through said channels and thus to abduct the heat generated within by the passage of electric current. As I have shown in my co-pending application mentioned above,

an arrangement of thissort'in connection with the stator of a high voltage dynamo will cause the electric effect of such a dygreater cross-sectional area adjacent the outer openingof the slot in which it is embeddedthan adjacent the bottom of said slot, or, in other words, according to the present invention I thus dispose the cooling channel in the conductor, so that two diametrically opposite parts of the channel walls are different in thickness I do this in order to obtain more favorable conditions of working with regard'to the suppression of the skin effect within the conductor. is well known to those skilled in the art, in a conductor mounted in a slot of an electric machine the electric current passing through said conductor is con centrated toward the open end of the slot with the result that in the parts of the conductor adjacent to the bottom of the slot little or no current will flow and in most cases even reverse currents will be generated at these places. This effect becomes most conspicuous in the case where a plurality of conductors are arranged within the slot above each other. New, by disposing the cooling channel spoken or" before within the conductors in such a manner that the conductor section is divided in two parts, a

comparatively broad solid part and a rather thin-walled hollow part, In 11 able to obtain the most favorable conditions with regard to the skin effect inasmuch as in a machine carrying within its-slots conductors of the kind described with the cooling channels near the bottom of the slots and the solid sectional part of the conductors adjacent to the slot openings, by far the greater area will be presented to the electric current, ac cumulating owing to the skin effect, near the slot openings, while owing to the bottom part ofthe conductor being hollow, no reverse current to speak of can be generated in that part.

As a matter of course the same applies to a plurality of conductors disposed one above the other in slots of an electric machine, for in each conductor .almost all the current assing through it will accumulate in the part nearest the slot opening.

in order to illustrate my invention 1 have shown in the drawings accompanying tle specification and formin part thereof a number of conductors of c orent form provided with cooling channels disposed in accordance with my invention, but i wish it to be understooc that the conductors shown are merely meant to he examp es not limiting my .lllVQllolOll which in be applied with substantially equal effect to any kind of conductor or combination of conductors used in a similar manner.

In the sections or slots chine. such to stator of a high v. doctors according to my inr therein.

Referring now to the drawings, Fig. 1 shows a conductor oi? rectangular crosssection with cooling channel eccentrically disposed within it so as to form a solid part 8 of a sectional area approximately equal to the portion in which the channel is disposed, the walls surrounding said channel on three sides being rather thin. This conductor is surrounded by a thick-walled insulating tube i and embedded with it in the slot in such a manner that the channel 0 is nearest to the bottom and the solid part 8 nearest to the opening of said slot.

In the modification shown in Fig. 2 two conductors of rectangular section disposed within a slot w, each conductor being formed similarly to the one shown in Fig. l with the exception of the cooling channels 0 0 which in this case have circular section, the solid area in this case being a little greater. Each of these conductors is surrounded by a thick-walled insulating tube 2 and the two conductors with their insulating tubes are disposed one above the other in the slot Q0 in such a manner that the channel c of the lowermost conductor is placed near the bottom of the slot and the channel 0 of the uppermost conductor is located 1 (llil adjacent to the top of the lowermost couductor.

In Fig. 3 a compound conductor made in two pieces is shown surrounded by a single insulating tube, a rectangular hollow conductor a being disposed in a slot 10 below a solid conductor a of substantially equal breadth and height.

The conductor shown in Fig. l is similar in outer shape to the one shown in Fig. l, the only difference being that here the conductor is made in two halves a and 6, each half showing one half of the solid part 8 and one half of the hollow part 0 of the conductor which is therefore similar to a conductor according to Fig. 1 cut in two halves in a vertical direction. The two parts a and Z) of this conductor are again held together by a thick-walled insulating tube i and are disposed within the slot in such a manner that the hollow part 0 is nearer to and the solid part 3 is farther away from the bottom of said slot.

I claim 1. An electric conductor provided with an eccentrically disposed longitudinal channel.

2. A hollow electric conductor having its hollow and solid parts disposed eccentricall-y.

An electric conductor bar provided with an eccentrica-lly disposed longitudinal channel.

An electric conductor in two pieces provided with an eccentrically disposed channel.

0. A composite electric conductor consist mg o'l' a solid conductor ahd a hollow conductor.

6. A composite electric conductor consisting of a metal bar and a metal tube.

7. In an armature of a dynamo electric machine having transverse slots, hollow conductors in said slots having their hollow and solid portions disposed eccentrically.

8. In an armature of a dynamo electric machine having transverse slot-s, hollow conductors having the hollow and solid portions disposed eccentrically and being located in said slots with the solid portions facing the periphery 01" the armature.

REINHOLD RUDENBERG. 

